Prince William and Kate Middleton have donned wrap-around safety goggles for a visit to a Rolls-Royce jet engine factory and took one of them for a spin.

William jumped at the offer to test one of the multimillion-pound machines during a guided tour of the state-of-art plant in Singapore, saying: "Yes we will," in a loud voice when asked by staff.

There was no chance of the sophisticated engine being damaged when the royals got their hands on it, as test engineers had set a limit on how hard the engine could be pushed.

Kate, wearing a white Alexander McQueen broderie anglaise suit, went first and sat down in front of a bank of screens and tentatively put her hand on the throttle as William watched.

The test facility at the huge open-plan plant began to rumble as the Trent 1000 engine, built for a Boeing 787 Dreamliner plane, sprang to life and began to whine and after a few moments the Duchess slowly brought it back to a stop.

Kate asked the test engineer who had been watching her every move: "Did that sound OK?" and he replied: "That was perfect, nothing wrong with that test."

The Duchess noticed some limit had been set on how far she could test the engine and when the engineer confirmed there was one, she asked, to laughter from other guests in the room: "So I wouldn't break (it)," which prompted the Duke to joke: "Try not to break any engines."

White hot: Kate wore a white Alexander McQueen suit on the second day of her tour (Image: Getty)

The royal couple walked through the vast space of the factory at Rolls-Royce's Seletar campus, which was opened in February and has begun building Trent 900 engines for the Airbus A380 double-decker plane.

Hundreds of staff had gathered to cheer the Duke and Duchess who were celebrating the British success story that is Rolls-Royce.

In a speech William said: "Here is cutting-edge aerospace technology developed by one of the United Kingdom's great global companies.

"I know that Rolls-Royce sets as its standard that it should be 'Trusted To Deliver Excellence'. There can be no doubt that Seletar will deliver exactly that."

Before leaving Kate was given the task of fitting the last of 24 fan blades to a Trent 900 engine. As she pushed a lever the titanium blade slotted home and she turned to William and Mark King, president of civil aerospace at Rolls-Royce, and pumped the air with her fist and smiled.

As the royal couple left they accepted a posy of flowers from Maeve Low, aged five, who was picked to make the presentation by the Make-A-Wish Foundation after she was given the all-clear from lymphoma.

William and Kate bent down to talk to the little girl, dressed in a bright pink dress and toy tiara, who was described as "princess mad" by her mother, Joanne Low, 38, a teacher from Singapore.

The royals spent a few minutes talking to the tongue-tied youngster who could only smile, but she did present them with some gifts - magic wands, a painting showing the Cambridges with Maeve's family and a cut-out photograph of the royal couple.

The Duke and Duchess posed for a photograph with their admirer before leaving to tour a housing project in Singapore.